Do you get that?
Count all the possibilities that are what you are looking for, then divide by the number of cards (52).
13 spades / 52 cards = ?
Ace King Queen Jack without a number (we could argue about Ace, I suppose)
so 9 cards with numbers in each suit of 13 (or count from 2 to 10 :) )
9 x 4 = 36 / 52 = ?